Among the existing mobile communication network services, 3G and 4G mobile communication services are being provided by separate networks, respectively. Further, recently, a 5G mobile communication network has been under development as a next generation mobile communication network. In addition, Wi-Fi and various near field communication services which used to be separately installed and operated have been provided as integrated services by interworking a mobile communication network with a next generation mobile communication network.
However, even if such technology and service providing methods are developed, network operators should continuously provide mobile communication services which have been provided in the past. For example, network operators should maintain and operate a 3G mobile communication networks to continuously provide services to existing 3G mobile communication service users even at the time when they mainly operate a 4G (also referred to as LTE) mobile communication networks for providing 4G mobile communication services. Furthermore, the network operators should try to improve service quality of the previous generation networks because of business competition between network operators.
In this situation, the network operator's burden of operation and management costs for the respective networks in operation for maintenance, repair, expansion, and quality improvement can be greatly increased. It can be worsen when the network operators try to adopt 5G or next generation mobile communication networks in their business because they may have to operate and manage multiple networks simultaneously.
In order to solve such a problem, a method of integrating services by interworking between heterogeneous wireless communication network apparatuses may be considered. However, it should be noticed that each hardware apparatus and functions for each wireless communication network should be manufactured in compliance with the domestic and foreign standards, so that the method of integrating network services by interworking between hardware apparatuses is very complicated and costly. Further, since each wireless communication network apparatus and function has kept individually developing, it should be getting more difficult to integrate networks and services on the premise of hardware apparatuses.
Particularly note that, in terms of physical performance of hardware apparatuses in a mobile communication network, the performance of a 4G network apparatus is generally superior to the performance of a 3G network apparatus in order to provide improved and new additional services. Further, such trend may be maintained so that a 5G or future network apparatus will have a much higher performance than its past generation 4G or 3G network apparatus. Thus, an efficient method for accommodating physical performances and service performances of the past generation networks as it is in the next generation network, avoiding to maintain the networks separately.
Recently, a software-defined networking (SDN)-based network architecture has been suggested to overcome the limitations exposed in the evolution and advancement of networks on the premise of hardware apparatuses. The SDN divides a network function into a control plane and a transmission plane in terms of software. Further, the SDN converts physical network elements positioned on the transmission plane into software virtual elements and controls and operates the virtual elements using a controller positioned on the control plane.
Further, network function virtualization (NFV) suggested together with the SDN is a technology of virtualizing functional elements of a network apparatus. The NFV technology defines an apparatus and its inherent function as software objects and controls these objects and thus makes it possible to control and operate each function through software.
As described above, recently, various next-generation network architectures using the software-based SDN and NFV have been suggested. However, such network architectures exclude consideration of interworking and integration of the past-generation network apparatuses being operated and the functions thereof.